//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <unordered_set>

// template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
//           class Alloc = allocator<Value>>
// class unordered_multiset

// iterator erase(const_iterator p)

#include <unordered_set>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

struct TemplateConstructor {
  template <typename T>
  TemplateConstructor(const T&) {}
};

bool operator==(const TemplateConstructor&, const TemplateConstructor&) { return false; }
struct Hash {
  std::size_t operator()(const TemplateConstructor&) const { return 0; }
};

int main(int, char**) {
  {
    typedef std::unordered_multiset<int> C;
    typedef int P;
    P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
    C c(a, a + sizeof(a) / sizeof(a[0]));
    C::const_iterator i      = c.find(2);
    C::const_iterator i_next = i;
    ++i_next;
    C::iterator j = c.erase(i);
    assert(j == i_next);

    assert(c.size() == 5);
    assert(c.count(1) == 2);
    assert(c.count(2) == 1);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);
  }
#if TEST_STD_VER >= 11
  {
    typedef std::unordered_multiset<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> C;
    typedef int P;
    P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
    C c(a, a + sizeof(a) / sizeof(a[0]));
    C::const_iterator i      = c.find(2);
    C::const_iterator i_next = i;
    ++i_next;
    C::iterator j = c.erase(i);
    assert(j == i_next);
    assert(c.size() == 5);
    assert(c.count(1) == 2);
    assert(c.count(2) == 1);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);
  }
#endif
#if TEST_STD_VER >= 14
  {
    //  This is LWG #2059
    typedef TemplateConstructor T;
    typedef std::unordered_set<T, Hash> C;
    typedef C::iterator I;

    C m;
    T a{0};
    I it = m.find(a);
    if (it != m.end())
      m.erase(it);
  }
#endif

  return 0;
}
